Chapter 25: assessment of the respiratory system Flashcards
Primary purpose of respiratory system
Gas exchange: transfer of O2 and CO2 bt atmosphere and blood
Upper respiratory tract
nose, mouth, pharynx, epiglottis, larynx, trachea
Turbinates
increase surface area of nasal mucosa which warms and moistens air as it enters the nose
Larynx
covered by epiglottis during swallowing
houses vocal cords
Trachea
-Carina
10-12 cm long
covered with U-shaped cartilage to allow swallowing
bifurcates at carina at angle of Louis at 4th and 5th vertebrae
Carina is super sensitive –> stimulation of it triggers intense coughing
Lower Respiratory tract
Bronchi
Bronchioles
Alveolar ducts
Alveoli
Lungs
-where is aspiration more likely to happen?
R = 3 lobes
L = 2 lobes
Mainstem bronchi, pulmonary vessels, and nerves enter at hilus
Right bc mainstem bronchi is straighter, shorter, and wider
Functional roles of each part of the lower airways
Trachea and bronchi = anatomic dead space (VD); no gas exchange
Bronchioles = smooth muscle constricts and dilates
Alveoli = terminal part of respiratory tract; gas exchange
Tidal volume and what part of that is dead space?
Tidal volume is about 500 mL
Of that, 150 mL is dead space
Alveoli: structure and function
main site of gas exchange with pulmonary capillaries
300 mil- each .3mm across
Connected by pores of Kohn –> let air pass, but also bacteria
Volume of 2500 mL
Surface area of a tennis court
Surfactant
lipoprotein secreted by alveoli when stretched
-reduces surface tension, making alveoli less likely to collapse
People take slightly larger breath (sigh) every 5-6 breaths to promote surfactant secretion
Atelectasis
collapsed alveoli
Big risk for post-op because anesthesia, decreased mobility, and pain alter breathing
In ARDS, lack of surfactant causes widespread atelectasis and collapse of lung tissue
Blood supply: Pulmonary circulation and Bronchial circulation
Pulmonary
-pulmonary artery brings deoxygenated blood to lungs from R ventricle
-gas exchange happens in capillaries
-pulmonary vein brings oxygenated blood to left atrium
Bronchial
-bronchial arteries branch off of thoracic aorta
-azygos vein brings deoxygenated blood to superior vena cava
Chest wall components
Thoracic cage
-12 pairs of ribs and sternum –> protect lungs and heart
Mediastinum
-space in middle of thoracic cavity
-houses heart, aorta, and esophagus
-separates R and L lungs into 2 separate compartments
Pleura
-visceral has no pain fibers/nerve endings, but parietal does –> that’s why inflammation can cause pain with breathing
-intrapleural space –> 20-25 mL fluid to lubricate during breathing and promote expansion of lungs during inspiration
Diaphragm
-major muscle of respiration
-innervated by R and L phrenic nerves from cervical vertebrae 3-5
-each side innervates one half (hemidiaphragm)
-damage above C3 paralyses entire diaphragm
Issues with intrapleural space
-usually fluid drains via lymphatic circulation
Pleural effuision = accumulation of fluid here
-can happen bc blockage of lymphatic drainage from cancer
-can happen bc of hear failure, causing imbalance bt intervascular and oncotic fluid pressure
Emphysema
-purulant pleural fluid with bacterial infection
Muscles during inspiration
Diaphragm: contracts and moves down
Internal intercostals: relax
External intercostals: contract
scalene: contract to raise ribs 1 and 2
Oxygenation
-normal partial pressure
-normal arterial saturation
Oxygenation = O2 from atmosphere to organs and tissues
-oxygen dissolved in plasma = partial pressure of oxygen in arterial blood (80-100)
-Oxygen bound to hemoglobin = arterial oxygen saturation (SaO2) –> (>95%)
O2 and CO2 move via diffusion until equilibrium is reached
Ventilation
-inspiration and expiration due to intrathoracic pressure changes and muscle action
-gas flows from higher pressure to lower pressure
Inspiration takes effort- expiration is passive
-elastic recoil = lungs bounce back after being stretched –> elastin in alveolar walls and around bronchioles
Ventilation issues
Dyspnea
-mandates that accessory muscles help expand thorax
Shallow breaths
-caused by phrenic nerve paralysis, rib fractures, neuromuscular issues
-lungs don’t fully inflate and gas exchange is impaired
Active expiration
-caused by exacerbations of asthma or COPD
-abs, intercostals, scalenes, and trapezius engaged
Compliance and Resistance
Compliance
-ease of lung expansion –> elasticity of lungs and elastic recoil of chest wall
-Decrease = hard to inflate; Increase = hard to recoil
-Decrease caused by fluid (pulmonary edema, ARDS, pneumonia); less lung elasticity (pulmonary fibrosis, sarcoidosis); or restriction of lung movement (pleural effusion)
-Increase caused by destruction of alveolar walls and less tissue elasticit (COPD)
Resistance
-airflow impeded during inspiration and/or expiration –> altered airway diameter
-asthma causes bronchoconstriction
-secretions are also an issue
Respiratory center
Medulla in brainstem
responds to chem and mech signals
sends impulses from spinal cord and phrenic nerve to respiratory muscles
Central Chemoreceptors
responds to changes in PaCO2 and pH in surrounding fluid
Central chemoreceptors in medulla
-increase H+ concentration = acidosis –> results in increased RR and VT (tidal v)
-decrease H = alkalosis –> decreased RR and VT
Increased PaCO2 = increased H2CO3 = decreased pH of CSF –> increased RR
Decreased Pa CO2 = decreased H2CO3 = increase pH of CSF –> decrease RR
Peripheral chemoreceptors
in carotid bodies and aortic bodies
-respond to decreased PaO2, decreased pH, and increased PaCO2
-stimulates respiratory center to increase RR
COPD - chronically increased PaCO2 –> desensitizes person to further increases
-maintain ventilation from hypoxic drive
-healthy person’s PaCO2 doesnt vary more than 3 mm Hg
Mechanical receptors
in conducting upper airway, chest walls, diaphragm, and alveolar capillaries
Stimulated by:
-irritants (conducting airway) –> stimulates cough
-stretch (smooth muscle) –> Hering Breuer reflex stops overdistension of lungs
-J receptors (alveolar capillaries) –> sense high pulmonary capillary pressure causing rapid shallow respiration seen in pulmonary edema
Respiratory Defense Mechanisms
Filtration of air – nasal hairs and shape of passage – 1um things get to alveoli
Mucociliary clearance – ciliary action fucked up by dehydration, smoking, too much O2, infection, alcohol, drugs (including anesthetics)
-COPD and cystic fibrosis are associated with destroyed cilia
Cough reflex – mucociliary clearance backup –> only effective for large or main airways
Reflex bronchoconstriction - response to inhaling a lot of irritants (also asthma)
Alveolar macrophages - bc there’s no cilia below resp. bronchioles –> bring stuff to cilia or lymph system –> can’t eat coal dust or silica –> damaged by smoking
Gerontologic changes in respiratory system
Structural changes
-calcification of costal cartilage = low chest expansion
-kyphosis (esp osteoporosis) leading to barrel chestedness + accessory muscle use
-resp. muscle strength declines, so lungs are harder to inflate
-less alveoli and less elastic
-lower airways close earlier, so gas exchange mostly happens in top part of lungs –> low PaO2
Defense mechanisms
-decrease in immunity
-macrophages start to suck; coughs are weaker; less functional cilia; drier membranes; less IgA; less feeling in pharynx = aspiration
Respiratory control
-more gradual response to O2 and CO2 levels
-smoking, obesity, and chronic illness put you at more risk of this
What to do during an assessment if respiratory distress is severe?
only get important info –> postpone the rest til condition has stabilized
Assessment: Health history
Upper: colds, sore throat, sinus infection
Lower: asthma, COPD, pneumonia, TB
Allergies: triggers, manifestations, and frequency
dyspnea could mean heart failure
frequent resp infections could mean HIV
Assessment: medications and surgeries
OTC, prescription, illicit, O2
*cough is common side effect of ACE inhibitors
ask about intubation, nebulizer, humidifier, airway clearance modality…
Functional assessment: health perception
-coughs
-sputum
-wheezes
-smoking
-vaccinations
-travel
-equipment
-perceived change in respiratory health (COPD changes might be too slow to notice)
-patient may relate change in symptoms rather than onset
-quality of cough: loose=secretions; hacking = irritation/obstruc.; bark = upper airway obstruction from subglottic edema –> chronic if over 3 weeks
sputum
-clear usually; gray with flecks in smokers; whitish yellow in COPD
-thick = dehydration; thin = post nasal drip or sinus drainage; pink and frothy = pulmonary edema
-hemoptysis = pneumonia, TB, lung cancer, and severe bronchiectasis
wheezes = obstruction -> asthma, aspiration, emphysema –> check for mycobacterium tuberculosis history too
smoking
-main risk for COPD
-pack years = packs per day times years smoked
vaccination
-flu and pneumonia
Travel
-TB risk in developing countries
-fungal lung infection risk if exposed to nature shit or immunocompromised ppl
Equipment
-make them show you how to use the inhaler
Genetic risks for respiratory stuff
cystic fibrosis
COPD
asthma
Functional assessment: nutrition
weight loss is symptom of resp disease
-anorexia, weight loss, and malnutrition = COPD, lung cancer, TB, bronchiectasis
-all metabolic demand is going to breathing
Dehydration or fluid retention can affect mucus and gas exchange
Functional assessment: elimination
-activity intollerance from dyspnea could lead to incontinence
-limited mobility from dyspnea could lead to constipation
-cough = stress incontinence
functional assessment: activity and excercise
-determine extent to which dypnea limits excersise and ADLS
-which positions make it better?
Immobility can lead to pneumonia
functional assessment: sleep-rest
asthma and COPD wake up with chest tightness/wheezing – need med change
heart probs = sleep sitting up to avoid orthopnea
sleep apnea in obese ppl = snoring, insomnia, waking abruptly
Night sweats = TB
functional assessment: cognitive-perceptual pattern
Hypoxia = restlessness, irritability, memory changes
-also inability to retain info, so can’t follow treatment instructions
Pain = pleurisy, fractured rib, costochondritis
functional assessment: self perception/concept
body image issues or embarrasment from equipment needed to tend to repiratory issues
-refer patient to support group
functional assessment: role/relationship
-assess degree to which resp issues or treatments interfere with work
-determine work/hobby exposure to irritants: coal, asbestos, silica
functional assessment: sexuality
-changes in activity
-positions that make it easier
-equipment needed to engage in it
functional assessment: coping/stress tolerance
dyspnea and anxiety exacerbate each other
-determine coping strategies and suggest support gp
functional assessment: value-belief
-determine level of adherence to plan
-in noncompliant, determine why (cultural reasons?)
-educate on benefits of treatment
Physical assessment: nose
-poly
-discharge
patency, inflammation, deformity, symmetry, discharge
polyp = allergies
purulent + malodorant discharge = foreign body
watery discharge = allergies or CSF
bloody discharge = trauma or dryness
thick discharge = infection
physical assessment: mouth and pharynx
color, lesions, masses, gums, dentition, bleeding
have them yawn if hard to see pharynx
stimulate gag reflex for nerves IX and X
Physical assessment: neck
symmetry, tenderness, swollen nodes
tender, hard, or fixed nodes = disease
Physical assessment: thorax and lungs
-do posterior chest first bc it gives the most info –> esp with females
-have patient lean forward with arms crossed
anterior chest- have patient sit up or semi-fowlers (30 degree)
Physical examination: inspection of thorax
appearance, position, evidence of respiratory distress
shape, symmetry, movement –> AP is 1/2 of T
respiratory rate, depth, and rhythm –> inspiration should be 1/2 as long as exprtn
-Cheyne-Stokes = rapid breathing with apnea breaks
-Biots = irregular breathing with apnea every 4-5 cycles
clubbing (over 180) = hypoxia –> usually nails get thicker and spongier
cyanosis = hypoxia or low cardiac output
Physical assessment: thorax palpation
-tracheal deviation
-chest expansion
-fremitus
Tracheal deviation
-away from tension pneumothorax or neck mass
-towards pneumonectomy or lobar atelectasis
Chest expansion
-hands at costal margin (ant) or 10th rib (post) with thumbs at midline
-thumbs should move 1” away from each other upon deep breathing
-absent or unequal expansion = atelectasis, pneumothorax, or pleural effusion
-decreased expansion = hyperinflation, barrel chest, or neuromuscular issues
Fremitus
-palms on back/chest while repeating phrase –> vibrations should be equal
-stongest at sternum and bt scapulae
-increase = fluid in the lungs or density or above pleural effusions
-decrease = hyperinflation or pleural effusion
-absent = pneumothorax or atelectasis
-back is easier than chest
Physical assessment: thorax Percussion
-in the intercostal spaces
-ant should be resonant over lung tissues except where heart or liver makes it dull
-post should be resonant until you get below diaphragm (flat)
Physical assessment: auscultation
-normal breath sounds
-adventitious breath sounds
-apex to base unless they’re in resp. distress or tire easily –> then do it backwards
-honestly, just look at diagram to figure out where to listen
Bronchial
-loud, high, hollow –> I/E ratio of 2:3 with gap bt –> trachea
Bronchovesicular
- med pitch and volume –> 1:1 ratio –> ant bt 1st and 2nd; post bt scapulae
Vesicular
-soft, low, rustles –> 3:1 –> all over lungs except major bronchi
Adventitous = wheezes, stridor, crackles, friction rub
-stridor is obstruction in upper airway; wheezes is lower
abnormal voice sounds
egophony = E sounds like A
bronchophony = spoken stuff sounds normal
whispered pectoriloquy = whispered stuff sounds normal
diagnostic studies in general
-Pulse oximetry and ABG
-If heart is working PaO2 or SaO2 will tell level of oxygenation –> can also assess CO2 for ventilation status
-If bad heart or hemodynamic instability (low conciousness, irreg HR, low BP), might have inadequate tissue O2 or abnormal O2 consumption –> have to evaluate mixed venous blood gas
Diagnostic studies: Oximetry
Pulse oximetry measures O2 saturation of hemoglobin –> 94-99%
-common inpatient, excersise testing, adjusting O2 flow rate, and perioperatively (bc anesthesia)
If under 70%, displays 4+- actual value
Innaccurate if other stuff is bound to hemoglobin
Other alterations = motion, low perfusion, anemia, cold extremeties, bright flourescent lights, intravascular dyes, thick acrylic nails, and dark skin
Diagnostic studies: ABGs
-blood test that measures oxygenation and acid-base balance
-PaO2, PaCO2, pH, HCO3, SaO2
PaO2 decreases with age and elevation
No changes to O2 15 mins b4 sample; use heparin syringe; apply pressure for 5 mins after
Diagnostic study: CO2 monitoring
Transcutaneous (PtCO2) or end tidal (PetCO2) capnography
PtCO2 = arterial pressure of CO2
PetCO2 = alveolar CO2 during exhalationg (peak)
-infrared light attached to tube
-if no tube, nasal cannula and capnometer
Diagnostic studies: mixed venous blood gases
Blood from pulmonary artery using catheter (one time) or fiberoptic sensor on central line (continuous)
-normal SvO2 is 60-80% and PvO ~40
-early sign of change in cardiac output or O2 delivery
CO2 a little higher; pH a little lower
Diagnostic studies: sputum studies
collected via expectoration, tracheal suction, or bronchoscopy
-can use sputum induction with irritating aerosol
Acid fast; culture/sensitivity; cytology; gram stain to determine microbe
Diagnostic study: skin tests
test for allergic reaction or exposure to TB bacilli or fungi
TB positive = exposure to antigen (doesn’t necessarily have TB)
TB neg = no exposure OR depression of cell mediated immunity (HIV)
5mm if HIV, contact with TB, immunosuppressed
10 mm if immigrant from certain places, druggie, lab worker, diabetes, kidney stuff
15 mm anyone
Diagnostic Studies: Bronchoscopy
-Bronchoalveolar lavage
bronchi are seen through fiberoptic tube
-obtain specimen
-remove stuff
-laser therapy, electrocautery, cryotherapy, and stents for patency
Can be outpatient –> patient can be supine to sitting
anethetize throat
-can do through endotracheal tube
CAUTION: verify consent; NPO; sedated
-After: NPO til gag returns –> monitor for hemorrhage or pneumothorax
BAL = sterile saline injected thru scope and withdrawn to examine cells
Diagnostic studies: lung biopsy
Can do it :
transbronchially, (foreceps or needle thru bronchoscope)
percutaneously/ via transthoracic needle aspiration, (through chest w/ CT or US)
-xray after to make sure no pneumothorax
by video assisted thoracic surgery
-rigid scope with lens goes through trocar into pleura via 1-2 incisions in thoracic cavity
-view inside via the scope and take the sample
-chest tube kept in place til lung expands
-safer than open
open lung biopsy
-open chest with thoracotomy incision
CAUTION
-monitor distress, pneumothorax, bleeding, incision/chest tube care, breath sounds –> encourage deep breathing
Diagnostic study: thoracentesis
large bore needle thru chest wall into pleural space to get specimen, remove fluid, or give meds
patient is upright
might leave in percutaneous catheter to drain fluid
Diagnostic studies: pulmonary function test
measure lung volumes and airflow
-diagnose/monitor disease; evaluate treatment; determine disability
spirometer and computer calculate values –> coaching to do deep inhale and fast, forceful, FULL exhale –> normal is 80-120% of predictions
if increase of 200 mL, positive bronchodilator response
Used by ppl with asthma, COPD, cystic fibrosis, lung transplants, and thoracic surgeries
Diagnostic studies: radiology
No metal –> check pregnancy
chest xray = common
CT –> check contrast/iodine allergy, renal func, hydration –> bad if warm/flushed
MRI –> no metal, check implants, address claustrophobia (sedation)
Ventilation-perfusion (V/Q) scan
Pulmonary angiogram -> contrast precautions; pressure dressing to injection site; monitor distal circulation
Positron emission tomography (PET) –> NPO prior; monitor glucose; FLUIDS
